1. Field of the Invention
The present invention relates to an imaging unit that captures an optical image of a subject while maintaining a high frame rate and reducing the occurrence of moire.
2. Description of the Related Art
A digital camera which comprises an imaging device having a great number of pixels and which can shoot both static images and moving images is known. When a moving image is shot using such a digital camera, generally the pixels ordered to output a pixel signal are limited in a process known as “thinning out”. Thus, in thinning out pixels, the pixel signal generated by a pixel (dependent on the amount of received light), is read and output from a subset of the pixels during the period for reading the pixel signals corresponding to an image.
By thinning out the pixels to output, the frame rate can be prevented from dropping. Consequently, the time it takes to read the pixel signals comprising an entire image can be shortened while the time it takes for a single pixel to generate and output a pixel signal is kept fixed. However, the problem arises that moire, (false pattern), occurs due to the loss a part of the complete image resulting from the thinning out of pixels.
In addressing for this problem, Japanese Patent Publication No. 2003-333610 discloses the generation of an image signal with a strength the same as that generated without thinning out by ordering all pixels to output pixel signals and performing a pixel mixing process on the output pixel signals. The pixel mixing process prevents moire from occurring. However, the time it takes to read the pixel signals comprising an entire image cannot be shortened because pixel signals should be output separately from all pixels in an imaging device.